This document discusses different types of boiler draught systems. It describes natural or chimney draught which relies on chimney height to create pressure differences. It also covers artificial draught systems like forced draught which uses fans to force air into the boiler, and induced draught which uses fans near the chimney to draw flue gases out. Balanced draught combines both forced and induced draught. Finally, it discusses steam jet draught systems, where a steam jet is used to create draught through either natural or forced methods.